The present invention relates to closures for containers, and specifically relates to a closure having a portion with a surface which engages the land surface of the container in a manner which prevents the unwanted escape or leakage of the container contents.
Conventional closures often are provided with some sort of formation for preventing the leakage of container contents, and such formations may take the form of gaskets, liners, annular sealing ribs, or other accepted sealing devices. Depending on the type of closure and/or the application, the efficiency of a particular sealing device may vary.
Conventional dispenser closures used for pouring the container contents often consist of three components, an inner sleeve which is friction-fit to the inside of the neck of the container, a spout portion which is either snap-fit into, or integrally formed with, the sleeve so that the spout projects vertically beyond the upper margins of the sleeve and the container neck, and a cap portion which is threaded onto the neck and may often serve as a measuring cup. This type of closure is commonly used for containers of liquid household laundry detergent and related products, although the closure seal of the invention is not restricted to any specific type of application.
A significant disadvantage of conventional dispenser closures is that the friction fitting of the closure over a container often results in an imperfect seal, due to variations in the land surface of the container. This problem is particularly prevalent when injection molded closures are used in combination with blow-molded bottles, in that the latter are inherently prone to variations in the land surface which may not provide a proper surface for sealing the closure thereon.
Although the application of sealing materials to the closure prior to assembly is known, such application has not been effective in solving the above-identified leakage problems. This is due in part to the fact that the sealing material often loses its resiliency or deformability prior to assembly.
Thus, there is a need for a container closure, and a method for securing such a closure upon a container, so that an underside surface of the closure, such as the above-described base portion, is sealingly secured to the land surface of the container to prevent the leakage of container contents, especially during pouring or inversion of the container.